CN110891642B

CN110891642B - Wire for medical treatment instrument and guide wire

Info

Publication number: CN110891642B
Application number: CN201880046632.8A
Authority: CN
Inventors: 橘昌臣; 宫本慎儿
Original assignee: Tokusen Kogyo Co Ltd
Current assignee: Tokusen Kogyo Co Ltd
Priority date: 2017-07-20
Filing date: 2018-06-26
Publication date: 2022-11-18
Anticipated expiration: 2038-06-26
Also published as: JP2019017856A; WO2019017164A1; JP6596470B2; US20200147353A1; CN110891642A

Abstract

The invention provides a wire for a medical treatment instrument and a guide wire. The outline shape of a cross section perpendicular to the longitudinal direction of the wire (2) is a circle having a diameter D. An imaginary circle (4) is assumed, and the imaginary circle (4) is concentric with a circle which is the outline shape of the wire (2) and has a diameter of 3/4 of the diameter D. On the virtual circle (4), a first measurement point (M1), a second measurement point (M2), a third measurement point (M3), a fourth measurement point (M4), a fifth measurement point (M5), a sixth measurement point (M6), a seventh measurement point (M7), and an eighth measurement point (M8) are assumed. The Vickers hardness (Hv) of these 8 measurement points was measured. The standard deviation σ of the 8 measurement values is 10 or less. The average value of the 8 measurement values is preferably 670 to 770 inclusive.

Description

Wire for medical treatment instrument and guide wire

Technical Field

The present invention relates to a wire suitable for use in a medical treatment instrument and a guide wire having a core obtained from the wire.

Background

In examination and treatment using a probe, a guide wire is inserted into a blood vessel. A probe is inserted into the vessel along the guidewire. The probe advances through the blood vessel while being guided by the guide wire. After the tip of the probe reaches a predetermined position, the guide wire is pulled out of the blood vessel. A contrast agent or the like is injected through the probe.

The guidewire has a core and a cladding that surrounds the core. Since the guide wire is used for the human body, the core is required to have corrosion resistance. The core is preferably austenitic stainless steel.

Since the blood vessel is curved, the guide wire inserted into the blood vessel travels while being curved. The physician may repeatedly move the guide wire back and forth in order to pass the guide wire through the stenosis. Even in such a use state, it is required that the core is not broken. In other words, the core is required to have fatigue resistance.

In a state where the guide wire is inserted into the blood vessel, the doctor operates a portion of the guide wire located outside the body. In this procedure, the physician rotates the guidewire. This rotational torque is transmitted to the tip of the guidewire. The core is required to have torque transmissibility.

An example of a guide wire excellent in fatigue resistance and torque transmission is disclosed in japanese patent laid-open No. 2009-172229.

Patent document 1: japanese patent laid-open publication No. 2009-172229

In a human body, there is a portion where blood vessels are bent at a steep angle. A strong bending stress is applied to the core of the guide wire passing through this portion. Therefore, the core of the guide wire passing through this portion needs further fatigue resistance. Thus, the filament as the material of the core also requires high fatigue resistance.

Even in various medical treatment instruments other than guide wires, the wires used for the medical treatment instruments are sometimes required to have high fatigue resistance.

Disclosure of Invention

The purpose of the present invention is to provide a wire for a medical treatment instrument, which has extremely excellent fatigue resistance.

In the wire for a medical treatment instrument according to the present invention, the outline shape of the cross section perpendicular to the longitudinal direction is a circle having a diameter D. In the cross section, the standard deviation σ of the vickers hardness of 8 measurement points located at equal intervals on a virtual circle concentric with the circle and having a diameter of (3/4) D is 10 or less.

The average value of the vickers hardnesses of the 8 measurement points is preferably 670 to 770 inclusive.

Preferably, the wire for a medical treatment instrument is made of stainless steel.

The tensile strength of the wire for a medical treatment instrument is preferably 2600MPa or more.

The wire for a medical treatment instrument preferably has a straightness of 0.10mm or less when the length of the wire is 2.00m.

From another perspective, the guidewire of the present invention has a core. The core has a cross-section perpendicular to the longitudinal direction and has a contour shape of a circle having a diameter D. In the cross section, the standard deviation σ of the vickers hardness of 8 measurement points located at equal intervals on a virtual circle concentric with the circle and having a diameter of (3/4) D is 10 or less.

Preferably, the core is made of stainless steel.

The tensile strength of the core is preferably 2600MPa or more.

The present inventors have found that breakage of the wire for a medical treatment instrument occurs due to stress concentration. The present inventors have found that the variation in the hardness of the wire in the circumferential direction is a cause of stress concentration. In the wire for a medical treatment instrument according to the present invention, the standard deviation σ of vickers hardness is small. The yarn is excellent in fatigue resistance.

Drawings

Fig. 1 is a perspective view showing a part of a wire for a medical treatment instrument according to an embodiment of the present invention.

Fig. 2 is an enlarged cross-sectional view showing the wire of fig. 1.

Fig. 3 is a front view showing the wire of fig. 1.

Fig. 4 is a schematic view showing the manufacturing apparatus of the yarn of fig. 1.

Figure 5 is a top view of a first orthotic showing the apparatus of figure 4.

Fig. 6 is an enlarged front view illustrating a correcting roller of the first corrector of fig. 5.

Fig. 7 is an explanatory view showing a measurement of the straightness of the wire of fig. 1.

Fig. 8 is a cross-sectional view showing a part of a guide wire according to an embodiment of the present invention.

Fig. 9 is a front view showing a core of the guide wire of fig. 8.

Detailed Description

Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings as appropriate.

Fig. 1 shows a wire 2 for a medical treatment instrument. The filaments 2 are elongate. The thickness of the filaments 2 is typically 2.0mm or less, in particular 1.0mm or less. The wire 2 is made of metal.

Fig. 2 shows a cross section of the wire 2. The cross-section is perpendicular to the length direction of the filaments 2. As can be seen from fig. 2, the cross-section has a circular profile. It is not necessary that the profile shape be a perfect circle. Even if the outline shape is a shape slightly different from a perfect circle due to a manufacturing error or the like, the outline shape is referred to as a "circle" in the present invention.

The diameter of the circle of the profile shape is indicated by arrow D in fig. 2. In other words, the diameter of the wire 2 is D. The two-dot chain line indicated by reference numeral 4 in fig. 2 is an imaginary circle. The imaginary circle is concentric with a circle that is the outline shape of the wire 2. The ratio of the diameter of the imaginary circle 4 to the diameter D is 3/4. Thus, as shown in FIG. 2, the distance from the surface of the filament 2 to the imaginary circle 4 is D/8.

A first measurement point M1 is assumed on the virtual circle 4. The position of the first measurement point M1 is determined randomly. Next, a second measurement point M2 is assumed to be provided on the virtual circle 4 at a position spaced 45 ° from the first measurement point M1 by the central angle of the virtual circle 4. Hereinafter, similarly, a third measurement point M3, a fourth measurement point M4, a fifth measurement point M5, a sixth measurement point M6, a seventh measurement point M7, and an eighth measurement point M8 are assumed at 45 °. These 8 measurement points are arranged at equidistant angles on the virtual circle 4.

For each of the 8 measurement points, vickers hardness (Hv) was measured. Vickers hardness is measured according to "JIS Z2244: 2009 "by microscopic vickers hardness tester. The measurement conditions were as follows.

Temperature: 23 deg.C

Loading: 100gf

Since 8 measurement points are provided, 8 measurement values (vickers hardness) can be obtained. The standard deviation σ of these measurements is calculated. The standard deviation σ is preferably 10 or less. In the medical treatment instrument wire 2 having the standard deviation σ of 10 or less, stress concentration in the circumferential direction is less likely to occur. The yarn 2 is excellent in fatigue resistance. When the yarn 2 is applied to a human body, breakage is not easily caused. From this viewpoint, the standard deviation σ is more preferably 8 or less, and particularly preferably 5 or less. Ideally the standard deviation sigma is zero.

The average Av of the 8 measured values (vickers hardness) is preferably 670 or more and 770 or less. The wire 2 for a medical treatment instrument having an average Av of 670 or more is excellent in torque transmissibility. From this viewpoint, the average value Av of the vickers hardnesses is more preferably 690 or more, and particularly preferably 700 or more. Filament 2, having an average Av below 770, is not brittle. The filaments 2 are therefore not easily damaged. From this viewpoint, the average value Av is more preferably 750 or less, and particularly preferably 740 or less.

The ratio of the standard deviation σ of the vickers hardness to the average Av is preferably 2.0% or less. In the medical treatment instrument wire 2 having the ratio of 2.0% or less, stress concentration in the circumferential direction is less likely to occur. The yarn 2 is excellent in fatigue resistance. When the yarn 2 is applied to a human body, breakage is not easily caused. From this viewpoint, the ratio is more preferably 1.5% or less, and particularly preferably 0.7% or less. Ideally this ratio is zero.

Fig. 3 is a front view showing the wire 2 for a medical treatment instrument of fig. 1. The full length of the filament 2 is indicated by the arrow L in fig. 3. The overall length L is the distance from the front end P1 to the rear end P2. In fig. 3, reference numeral P3 denotes a point at a distance L × 0.1 from the leading end P1, reference numeral P4 denotes a point at a distance L × 0.5 from the leading end P1, and reference numeral P5 denotes a point at a distance L × 0.9 from the leading end P1.

The filament 2 is cut at point P3 to obtain a first cross section. The first cross-section is perpendicular to the length direction of the filaments 2. In the first cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In this first section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio (σ/Av) described above are realized.

The filament 2 is cut at point P4 to obtain a second cross-section. The second cross-section is perpendicular to the length direction of the filaments 2. In the second cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In this second cross section, as in the first cross section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio (σ/Av) described above are also realized.

The filament 2 is cut at point P5 to obtain a third cross-section. The third cross-section is perpendicular to the length direction of the filaments 2. In the third cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In the third cross section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio (σ/Av) described above are also realized, as in the first cross section.

Fig. 4 is a schematic view showing the filament manufacturing apparatus 6 of fig. 1. The apparatus 6 has a wire drawing machine 8, a wire drawing cross-over machine 10, and a second straightener 12. The drawing machine 8 has a first cone 14, a second cone 16, a plurality of dies 18, a first straightener 20, and a final die 22. The first cone 14 has a plurality of rollers 24 of different diameters. The second cone 16 also has a plurality of rollers 26 of different diameters. The base wire 27 is bridged in tension between the first cone 14 and the second cone 16. The base wire 27 passes through the die 18 on its way from the first taper 14 towards the second taper 16. The base wire 27 travels from the

small diameter rollers

24, 26 to the

large diameter rollers

24, 26. By this travel, the base wire 27 is elongated and reduced in diameter. The base wire 27 passes through the first aligner 22, the final die 22, the wiredrawing interface 10, and the second aligner 12.

Figure 5 is a schematic diagram illustrating the first appliance 20 of the device 6 of figure 4. Although not shown, the second appliance 12 has the same configuration as the first appliance 20. The first straightener 20 has a plurality of straightener rollers 28 arranged in a serrated pattern. In the embodiment of fig. 5, the number of the leveling rollers 28 is 11.

Fig. 6 is an enlarged front view illustrating the correcting roller 28 of the first corrector 20 of fig. 5. The correcting roll has a correcting groove 29. The width of the straightening groove 29 is approximately the same as the diameter of the base wire 27. In the embodiment of fig. 5, the number of the leveling rollers 28 is 11. The base wire 27 runs along these leveling rollers 28 in a zigzag manner. In the base wire 27, the entire surface portion thereof is repeatedly subjected to bending processing by the correction groove 29. This improves the uniformity of hardness of the surface portion.

After the processing by the apparatus 6 shown in fig. 4 and 5, the base wire 27 is cut into a predetermined length, and further subjected to heat treatment to obtain the wire 2 for a medical treatment instrument. By examining the drawing conditions, the wire 2 having a small standard deviation σ can be obtained. The present inventors have found that a wire 2 having a small standard deviation σ can be obtained by setting the conditions for final drawing to the following conditions.

Number of appliances: 2

Installation position of the aligner: front and back of the final mold

Number of correcting rollers: 9-13

Tension of base wire at outlet of straightening machine: 40-70% of breaking load

The heat treatment is preferably performed under a hydrogen atmosphere. In the heat treatment under this atmosphere, heat is conducted to the base wire in a short time. The temperature of the heat treatment is from 500 to 650 ℃.

The preferred material for the wire 2 is stainless steel. Stainless steel is excellent in corrosion resistance and strength. Specific examples of the stainless steel include austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, precipitation hardening stainless steel, and duplex stainless steel. Austenitic stainless steels are preferred. Other preferable materials of the wire 2 are Ni — Ti alloy and Ti alloy.

The tensile strength of the yarn 2 is preferably 2600MPa or more. The yarn 2 having a tensile strength of 2600MPa or more is excellent in the propelling property when the yarn 2 travels in the human body. From this viewpoint, the tensile strength is more preferably 2700MPa or more, and particularly preferably 2800MPa or more. The tensile strength is preferably 3000MPa or less.

The tensile strength was measured according to the regulations of "JIS Z2241 (2011)". The measurement conditions were as follows.

Temperature: 23 deg.C

Stretching speed: 10mm/min

Scoring distance: 100mm

Fig. 7 is an explanatory view showing a measurement of the straightness of the wire 2 of fig. 1. In this measurement, the vicinity of the upper end of the wire 2 is held by the jig 30. The portion of the wire 2 not clamped is referred to as the free portion 32. The only force acting on the free portion 32 is gravity. In fig. 7, a point P6 indicates the upper end of the free portion 32, and a point P7 indicates the lower end of the free portion 32. The distance from the upper end P6 to the lower end P7 was 2.00m. The two-dot chain line in fig. 7 extends in the vertical direction. In fig. 7, denoted by reference sign S is the distance (mm) of the lower end P7 from the two-dot chain line. The distance S is the amount by which the lower end P7 of the wire 8 is offset from the plumb line. The distance S is the straightness. The wire 8 having a small distance S has excellent linearity. In the case of a wire having poor linearity, the distance S has a large value due to the bending of the wire.

The straightness S of the filament 2 is preferably 0.10mm or less. The wire 2 having a straightness S of 0.10mm or less is excellent in torque transmission. From this viewpoint, the straightness S is more preferably 0.05mm or less, and particularly preferably 0.02mm or less. Ideally, the straightness S is zero.

Fig. 8 is a cross-sectional view showing a part of a guide wire 34 according to an embodiment of the present invention. In fig. 8, the left end is the end 36 and the right end is the rear end 38. The guide wire 34 includes a cladding 40, a core 42, a coil 44, and a fixing material 46. The overall length of the guidewire 34 is typically from 1500mm to 2300mm. The wire diameter (thickness) of the guidewire 34 is typically from 0.30mm to 0.60mm.

The cladding 40 covers the core 42. The coating 40 is made of synthetic resin. A typical synthetic resin is teflon resin. The coating 40 can provide smoothness when the guide wire 34 is inserted into a blood vessel.

The core 42 is provided with a main portion 48 and a tapered portion 50. The wire diameter of the main portion 48 is practically constant. The wire diameter of the main portion 48 is typically from 0.25mm to 0.50mm. The tapered portion 50 tapers in diameter toward the distal end 36.

The coil 44 is wound around the tapered portion 50. The coil 44 reinforces the tapered portion 50 without impairing the flexibility of the tapered portion 50. The securing material 46 is secured to the core 42.

The core 42 is formed of the wire 2 for a medical treatment instrument shown in fig. 1 to 3. The core 42 is obtained by grinding the vicinity of the end 36 of the wire 2. Typically, grinding is performed by a centerless grinder. The tapered portion 50 is formed by grinding.

As described above, since the core 42 is formed of the wire 2 for a medical treatment instrument shown in fig. 1 to 3, the standard deviation σ, the average value Av, and the ratio (σ/Av) of the vickers hardness of the core 42 are the same as the standard deviation σ, the average value Av, and the ratio (σ/Av) of the vickers hardness of the wire 2 for a medical treatment instrument. The material, tensile strength, and straightness S of the core 42 are the same as those of the wire 2 for a medical treatment instrument. The core 42 is therefore excellent in fatigue resistance and torque transmission. When the guide wire 34 is inserted into a curved portion of a blood vessel, the core 42 is less likely to be damaged even if the doctor repeats the forward and backward movement of the guide wire 34. If the physician turns the guidewire 34 near the trailing end 38, its torque is transmitted to the tip 36. The physician can smoothly manipulate the guidewire 34.

Since the core 42 has the tapered portion 50, the vickers hardness cannot be measured by the method shown in fig. 3. The measurement method instead of this method is shown in fig. 9. In fig. 9, reference numeral P8 denotes a boundary between the main portion 48 and the tapered portion 50, and an arrow L denotes the entire length of the main portion 48. The overall length L is the distance from the boundary P8 to the rear end P9. In fig. 9, reference numeral P10 denotes a point at a distance L × 0.1 from the boundary P8, reference numeral P11 denotes a point at a distance L × 0.5 from the boundary P8, and reference numeral P12 denotes a point at a distance L × 0.9 from the boundary P8.

The core 42 is cut at point P10 to obtain a first cross section. The first cross-section is perpendicular to the length of the core 42. In the first cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In this first section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio of the standard deviation σ to the average Av described above are realized.

The core 42 is cut at point P11 to obtain a second cross section. The second cross-section is perpendicular to the length of the core 42. In the second cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In this second cross section, as in the first cross section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio of the standard deviation σ to the average Av are realized.

The core 42 is cut at point P12 to obtain a third cross-section. The third cross-section is perpendicular to the length of the core 42. In the third cross section, the first measurement point M1, the second measurement point M2, the third measurement point M3, the fourth measurement point M4, the fifth measurement point M5, the sixth measurement point M6, the seventh measurement point M7, and the eighth measurement point M8 are assumed. The Vickers hardness was measured at these measurement points. In this third cross section, as in the first cross section, the range of the standard deviation σ, the range of the average Av, and the range of the ratio of the standard deviation σ to the average Av are realized.

Examples

The effects of the present invention will be clarified by the following examples, but the present invention should not be construed as being limited to the descriptions of the examples.

[ example 1]

The base wire made of SUS304 was repeatedly subjected to wire drawing and heat treatment. By drawing, the base wire is elongated while being reduced in diameter. In the final drawing step, straightening is performed by a straightener provided before and after the finishing die. The wire diameter in the final drawing step is

The correction conditions were as follows.

Diameter of the leveling roller: 10mm

Number of correcting rollers: 11

Tension of the base wire in the orthosis: 190N (finish mold inlet)

170N (finish mold outlet)

And carrying out low-temperature annealing on the base wire subjected to final wire drawing to obtain the core for the guide wire. The conditions of the low temperature annealing were as follows.

Atmosphere temperature: 575 deg.C

Retention time: 60min

Atmosphere gas: hydrogen

[ example 2]

The core of example 2 was obtained in the same manner as in example 1 except that the number of leveling rollers of the leveling device was changed as follows.

Number of correcting rollers: 9

[ example 3]

A core of example 3 was obtained in the same manner as in example 1 except that the tension of the base wire of the orthosis was set as follows.

Tension of the base wire in the orthosis: 175N (finish mold inlet)

155N (finish mold outlet)

[ example 4]

The core of example 4 was obtained in the same manner as in example 3 except that the number of leveling rollers of the leveling device was changed as follows.

Number of correcting rollers: 9

Comparative example 1

A core of comparative example 1 was obtained in the same manner as in example 1 except that no aligner was used in the final drawing step.

Comparative example 2

A core of comparative example 2 was obtained in the same manner as in example 1 except that the number of the resist rollers of the resist device and the tension of the base yarn were set as follows.

Number of correcting rollers: 18

Tension of the base wire in the orthosis: 190N (finish mold inlet)

190N (finish mold outlet)

[ evaluation ]

The average value and standard deviation of the section hardness were measured by the above-mentioned methods. Tensile strength and straightness of the core were determined using the methods described above. And, the fatigue value of the core was measured. The fatigue value was measured using a Hunter fatigue tester manufactured by BEKAERT. The stress of the test was set to 1000-1500MPa in an atmosphere with a humidity of 40%, and the total of 5 test samples was 10 ⁷ The fatigue limit stress of (2) is taken as the fatigue value. Knot of itAs shown in table 1 below.

[ Table 1]

TABLE 1 valuation results

The evaluation results in Table 1 show that the advantages of the present invention are clear.

Industrial applicability

The wire according to the present invention can be applied to various medical treatment instruments.

Description of the reference numerals

2 … a wire for a medical treatment instrument; 4 … an imaginary circle; 6 … manufacturing apparatus; 8 … wire drawing machine; 10 … wire drawing and cross connecting machine; 12 … a second appliance; 14 … first cone; 16 … second cone; 18 … die; 20 … a first appliance; 22 … final die; 24. 26 … roll; 27 … base filament; 28 … leveling rollers; 29 … correction slot; a 30 … clamp; 32 … free portion; 34 … guidewire; 40 … cladding; 42 … core; 44 … coil; 48 … main section; 50 … taper.

Claims

1. A wire for a medical treatment instrument, wherein,

the contour shape of a cross section perpendicular to the longitudinal direction of the wire for a medical treatment instrument is a circle having a diameter D,

the standard deviation sigma of the Vickers hardness of 8 measurement points located at equal intervals on a virtual circle concentric with the circle and having a diameter of 0.75D on the cross section is 10 or less,

the wire for the medical treatment instrument is made of stainless steel.

2. The wire for a medical treatment instrument according to claim 1, wherein,

the average value of the vickers hardnesses of the 8 measurement points is 670 to 770 inclusive.

3. The wire for a medical treatment instrument according to claim 1 or 2, wherein,

the tensile strength of the wire for a medical treatment instrument is 2600MPa or more.

4. The wire for a medical treatment instrument according to claim 1 or 2,

the wire for a medical treatment instrument has a straightness of 0.10mm or less when the length of the wire is 2.00m.

5. The wire for a medical treatment instrument according to claim 3, wherein,

6. A guide wire, wherein,

the guidewire has a core with a proximal end and a distal end,

the profile shape of a cross section of the core perpendicular to the length direction is a circle with a diameter D,

the core is made of stainless steel.

7. The guidewire of claim 6,

8. The guidewire of claim 6 or 7, wherein,

the tensile strength of the core is 2600MPa or more.